1. Field of the Invention
The present invention relates to door mounted alarm systems, and more particularly to a lock set with a self-contained alarm/annunciator system such as for use in a door and operable without external wiring or extensive modification to the door frame.
2. Description of the Prior Art
The ever increasing number of residential burglaries in recent years has intensified the need for alarm systems. Typical residential alarm systems may include a plurality of sensor mechanisms at various entrance points connected by external wiring to an indicator panel or some other control panel, and may further include a communication link for alerting law enforcement authorities to a break-in. Unfortunately, while such alarm systems may provide a number of desirable features, they are often expensive, and in the case of a retrofit system, may require extensive external wiring and modification to the dwelling such as to the frame surrounding the door.
Today, as many as 85-90 percent of all residential burglaries are perpetrated by nonprofessional burglars who are oftentimes easily scared off. While expensive and complicated alarm systems which require extensive external wiring and door frame modification may provide a wide range of deterrence features, their cost and complexity may not be necessary to deter a majority of the residential burglaries. For example, an alarm system which merely creates a loud alarm sound upon an attempted unauthorized entry may often deter the would-be residential burglar. Therefore, deterrence ability becomes an important focus of residential alarm systems.
It has been proposed to provide a limited function, self-contained alarm unit for application to a door, for example, wherein the self-contained system includes arming circuitry, alarm sensor, and alarm sounding system all in a single housing. Some of these door mounted alarm systems may also integrate a door locking mechanism such that the alarm unit is armed when the door is locked and disarmed otherwise. However, such self-contained lock and alarm systems can be of limited utility and may not provide a desirable range of deterrence features.